Semiconductor module including components in plastic casing

ABSTRACT

A semiconductor module includes components in a plastic casing. The semiconductor module includes a plastic package molding compound and a semiconductor chip. Also provided in the module are a first principal surface including an upper side of the plastic package molding compound and at least one active upper side of the semiconductor chip, a second principal surface including a back side of the plastic package molding compound, and a multilayered conductor track structure disposed on the first principal surface and a second metal layer disposed on the second principal surface.

RELATED APPLICATIONS

This application is a continuation-in-part application of prior U.S.application Ser. No. 11/421,684, filed Jun. 1, 2006, which applicationclaims priority to German application nos. 10 2006 023 123.6, filed May16, 2006 and 10 2005 025 150.1, filed Jun. 1, 2005, the disclosures ofwhich are incorporated herein by reference in their entirety.

TECHNICAL FIELD

Aspects of the invention relate to a semiconductor module includingcomponents in a plastic casing.

BACKGROUND

Semiconductor devices with plastic housing compositions are inwidespread use in semiconductor electronics. On the one hand, theplastic housing composition is intended to protect and hold together theelectronic components and, on the other hand, in so far as internalwirings are provided within the semiconductor device, they are intendedto be electrically insulated from one another by the plastic housingcomposition.

SUMMARY

A semiconductor module includes components in a plastic casing.According to an illustrative aspect, a first principal surface includesan upper side of a plastic package molding compound and at least oneactive upper side of a semiconductor chip and a second principal surfaceincluding a back side of the plastic molding compound. According to afurther aspect, a multilayered conductor track structure is disposed onthe first principal surface and a second metal layer is disposed on thesecond principal surface.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative aspects of the invention will be explained in detail withreference to the appended figures. The figures are only schematic andnot to scale; thin-film layers in particular are shown asdisproportionately thick for better representation.

FIG. 1 is a schematic cross section through a semiconductor module of afirst illustrative embodiment;

FIG. 2 is a schematic cross section through the semiconductor moduleaccording to FIG. 1, with possibilities for application of connectingelements;

FIG. 3 is a schematic cross section through the semiconductor moduleaccording to FIG. 1 with a connecting element to a surface-mountableexternal contact on the lower side of the semiconductor module;

FIG. 4 is a schematic cross section through the semiconductor moduleaccording to FIG. 1 with a bond wire connecting element to a contactconnecting surface of a superordinate printed circuit board;

FIG. 5 is a schematic cross section through the semiconductor moduleaccording to FIG. 1 with a solder ball connecting element to a contactconnecting surface of a superordinate printed circuit board;

FIG. 6 is a schematic cross section through the semiconductor module ofa second illustrative embodiment;

FIG. 7 is a schematic cross section through the semiconductor moduleaccording to FIG. 6, with a first illustrative modification of theantenna structure;

FIG. 8 is a schematic cross section through the semiconductor moduleaccording to FIG. 6, with a second illustrative modification of theantenna structure;

FIG. 9 is a schematic cross section through the semiconductor moduleaccording to FIG. 6, with a third illustrative modification of theantenna structure;

FIG. 10 is a schematic cross section through the semiconductor moduleaccording to FIG. 6, with a fourth illustrative modification of theantenna structure;

FIG. 11 is a schematic cross section through a semiconductor module of athird illustrative embodiment;

FIG. 12 is a schematic view of the semiconductor module from below,according to FIGS. 6 to 11;

FIG. 13 is a schematic cross section through a semiconductor module of afourth illustrative embodiment;

FIG. 14 is a schematic cross section through a semiconductor module of afifth illustrative embodiment; and

FIG. 15 illustrates a semiconductor module of a sixth illustrativeembodiment.

DETAILED DESCRIPTION

Illustrative aspects of the invention provide a semiconductor moduleincluding components for microwave engineering in a plastic casing. Forthis purpose the semiconductor module has a principal surface includingan upper side of a plastic package molding compound and at least oneactive upper side of a semiconductor chip. Disposed on the principalsurface is a multilayered conductor track structure which alternatelyincludes structured metal layers and structured insulation layers. Atleast one of the insulation layers and/or the plastic package moldingcompound has at least one microwave insulation region.

This semiconductor module may have the advantage that the plastic casingprovides a “quasi”-monolithic block which includes all the componentsfor a semiconductor module for microwave engineering. Providing at leastone microwave insulation region, either in the insulation layersprovided on the plastic casing or inside the plastic package moldingcompound of the plastic casing, can have the advantage that not only thesemiconductor chips required for the function of the semiconductormodule can be embedded in the quasimonolithic block of a plastic casingbut also an antenna structure is an integral component of the plasticcasing.

In addition, it can be beneficial that the entire plastic packagemolding compound or a complete insulation layer does not include amaterial suitable for microwave engineering but it is entirely possibleto provide at least one microwave insulation region in the insulationlayers and/or in the plastic package molding compound of the plasticcasing.

For this purpose, the microwave insulation region may have a relativedielectric constant ∈_(r) between 1≦∈_(r)≦2.5. Plastic foams having arelatively low specific weight can also be used to implement this typeof microwave insulation region. These foam materials have typical poresizes of 0.4 mm. If the microwave insulation region is miniaturizedfurther, however, material properties which are no longer homogeneouscan be obtained for these types of foam materials, which means that the∈_(r) tolerances become impermissibly large.

It is indeed possible to freely mill a relevant microwave insulationregion in printed circuit boards as carriers of a microwave module sothat an ∈_(r) of approximately 1 is constructively feasible. Herethough, the milling technique has dimensional limits below which it isnot easy to go so that limits are consequently also imposed on theminiaturization. In addition, it can be difficult to produce blind holeswhich end at a metal layer by milling. Furthermore, while milling doesallow the fabrication of blind holes, this may be cost-intensive and thecosts increase with smaller dimensions.

A further possibility for creating through holes and therefore microwaveinsulation regions with ∈_(r)˜1 is to use a laser removal method butthis also can be expensive. In addition, none of these methods allowsany kind of undercuts which are possibly advantageous especially for apatch antenna structure with apertures.

These limitations are surmounted for the first time by the solution sothat antenna structures can also be implemented as an integral componentof a semiconductor module with components for microwave engineering in aplastic casing. In addition, the use of a casing may have the advantagethat a principal surface including a semiconductor chip surface andplastic package molding compound surface is available, which providesflat surfaces having relatively low topography for subsequent thin-filmprocessing of conductor track connections to electrodes of semiconductorchips and for the provision of slotted electrodes, striplines, andradiation plates of patch antenna structures in different metal layers.

In an illustrative embodiment, the semiconductor module can have amicrowave insulation region for a patch antenna structure or a stripantenna structure or a slotted antenna structure with correspondinglymatched radiation plate.

In one aspect an antenna structure which operates with an antennacoupling region in the insulation layer and/or the plastic packagemolding compound and advantageously has no ohmic contact between anenergy-supplying stripline and a spatially radiating antenna plate.

In an illustrative embodiment, a coupling cavity may be provided in theplastic package molding compound or in an insulation layer as themicrowave insulation region. In a coupling cavity a relative dielectricconstant ∈_(r) with ∈_(r)˜1 is automatically provided. For this purpose,the antenna coupling region is covered by the radiation plate. Anaperture or a coupling slot for coupling-in the microwave energy isprovided opposite to the radiation plate. In one aspect, the aperturecan be formed by a slotted electrode. This slot of a slotted electrodeis intersected by a spaced stripline for a polarized antenna coupling ofa polarized patch antenna structure, at a distance from the slottedelectrode.

In a further illustrative embodiment, the aperture is formed by adouble-slotted electrode having coupling slots arranged orthogonally toone another with each being intersected at a distance by spacedstriplines for a dual-polarized antenna coupling of a dual-polarizedaperture-coupled patch antenna structure.

It is further provided that the semiconductor module includes adielectric lens which is disposed above the radiation plate. This canhave the advantage that the directionality of the antenna structure canbe further improved and the coupling to space is more effective.

In one aspect, the spacing between the aperture and radiation platecorresponds to the thickness of the insulation layer in the microwaveinsulation region. This type of construction has the advantage that oneof the upper insulation layers on the plastic casing having a relativedielectric constant in the range of 1≦∈_(r)≦3.5 can be used as standardthroughout for the antenna coupling region. In addition to the couplingof the radiation plate, this insulation layer can additionally be usedas a pure insulation layer between two structured metal layers.

In a further illustrative embodiment, it is provided that the spacingbetween aperture and radiation plate corresponds to the thickness of aplastic package molding compound of a plastic casing and is disposed asa coupling cavity in the plastic package molding compound and is matchedto different coupling frequencies of the antenna structure. This has theadvantage that the height of the coupling cavity can be defined at thesame time as the thickness of a plastic casing and by varying thethickness of the plastic casing, matching to different couplingfrequencies of the antenna structure can be achieved by constructivemeasures without any problems.

In addition to producing different plastic casing thicknesses of aplastic casing, matching of the antenna structure to different couplingfrequencies can be provided by special constructive measures in the areaof the antenna structure, different from the thickness of the plasticcasing. For this purpose, the spacing between aperture and radiationplate can be matched to different coupling frequencies of the antennastructure by arranging the aperture on different metal layers of themultilayered conductor track structure on the principal surface. In thiscase, the possibility of using the different levels of the metal layerson the principal surface is used to match to different couplingfrequencies.

A further possibility for matching the different coupling frequencies ofthe antenna structure consists in matching the spacing between apertureand radiation plate to the coupling frequency of the antenna structureby different shaping of a base surface of a dielectric lens. For thispurpose, the base surface of the dielectric lens can be constructed as amesa structure where the mesa structure bears the radiation plate. Inaddition, it is possible that the base surface of the dielectric lenshas an indentation in which the radiation plate is disposed. In the caseof the mesa structure, a higher coupling frequency can be achieved andin the case of the indentation in the dielectric lens, a reducedcoupling frequency will result.

In addition, it is easily possible to dispose a VCO for extremely highfrequencies in the plastic package molding compound. The VCO may bedisposed adjacent to the microwave insulation region with the antennastructure. With this construction the strip line from one electrode ofthe VCO semiconductor chip to an aperture of a slotted electrodearranged at a distance can be executed in a manner such that signalreflections and the coupling-in of electromagnetic interference fieldsare minimized. In no hitherto-known technology is it possible to producesuch an optimally matched connection between a VCO semiconductor chipand a patch antenna structure.

Furthermore, other semiconductor chips such as a DSP (digital signalprocessor) semiconductor chip for microwave components can be embeddedin the plastic package molding compound so that these semiconductorchips are arranged adjacent to the microwave insulation region withantenna structure.

The semiconductor module can have not only individual antennas butantenna structures with antenna arrays which are arranged in a microwaveinsulation region. These antenna structures can be arranged in a squareor in a rectangle, respectively one antenna structure being arranged inone corner of the square or the rectangle. These antenna arrays can alsobe arranged in an edge zone of a semiconductor module in a line or inrows. These antenna arrays do not have external contacts but areconnected to the semiconductor chip by direct leads on the principalsurface of the plastic casing. Consequently, regions of thesemiconductor module are obtained which cannot be supported onelectrically conducting external contacts such as solder balls so thatthese regions are arranged almost suspended on a superordinate circuitboard. In order to stabilize and support these regions in anadvantageous manner, the semiconductor module can have surface-mountablesolder balls which are partly provided as mechanical supports and/orspacers of the semiconductor module for surface mounting on asuperordinate circuit board.

In a further illustrative embodiment, heat sinks are provided on a sideof the semiconductor module opposite to the external contacts or thesolder balls for support functions. These heat sinks can be connected tothe back side of the plastic casing by a heat-conducting adhesive layeror solder layer so that they are firmly bonded. In addition, the heatsink can have cooling fins which intensively radiate the heat to thesurroundings and/or can deliver it by convection. In an illustrativeembodiment, the cooling fins of the heat sink are arranged such that thesemiconductor module is fixed on the heat sink between the cooling fins.In addition, the cooling fins between which the semiconductor module isarranged can themselves have solder balls which are used for themechanical fixing on a superordinate circuit board.

A screening case can also be used as heat sink, the semiconductor modulebeing fixed on an inner side of the screening case. Solder ballsarranged on the cooling fins of the heat sink or solder paste on theside wall ends of the side walls of a screening case can form a planewith the external contacts of the semiconductor module, wherein theexternal contacts and the solder balls of the heat sink or the solderpaste of the screening case are surface-mounted. Furthermore, the heatsink and a patch antenna structure can be arranged on the back side ofthe semiconductor module. This has the advantage that the heat sinksurrounding the patch antenna structure can at the same time function asa groundplane and thus improves the directional characteristic of thepatch antenna.

If a semiconductor module of this type is used in a distance detectionradar for vehicles, it can be advantageous if this distance detectionradar has antenna structures arranged at least in one line.Semiconductor modules whose antenna arrays are arranged on a square orrectangular surface and occupy at least the corners of this square orrectangular surface with respectively one antenna structure, are used asnavigation equipment with satellite-assisted global position detection.Transponders can also be fitted with a semiconductor module of this typeto allow a global position enquiry of a device or vehicle using asemiconductor module.

Two methods can be used for fabricating a semiconductor module withcomponents for microwave engineering in a plastic casing. One method canbe used to build or produce antenna structures with a cavity resonatorof a plastic package molding compound as an integral component of aplastic casing and another method yields a semiconductor module with anantenna structure, the antenna structure being provided in an insulationlayer having a relative dielectric constant ∈_(r) between 1≦∈_(r)≦3.5 ofa plastic casing.

In the method for fabricating a semiconductor module with components formicrowave engineering in a plastic casing, where the plastic casing hasa resonator cavity for an antenna structure, the following process stepscan be carried out successively.

Firstly, components of the semiconductor module including at least onesemiconductor chip for extremely high frequencies with electrodes on anactive upper side and/or including passive components with correspondingelectrodes on a connecting plane are fabricated. In preparation for thecoupling cavity of the antenna structure, at least one sacrificialmaterial structure for a microwave insulation region of thesemiconductor module is produced. After this fabrication of singlecomponents, the semiconductor chip, the passive components with theirelectrodes, and the sacrificial material structure are applied to anupper side of a subcarrier. The sacrificial material structure is theninserted at relevant points similar to the placement of semiconductorchips on the subcarrier. The components are then embedded or laminatedin a plastic package molding compound on the subcarrier.

The subcarrier can then be removed so as to expose a principal surfaceincluding plastic package molding compound, electrodes, and an upperside of the sacrificial material structure and so as to form a compositeboard. A multilayered conductor track structure is applied to theprincipal surface on this composite board by applying structuredinsulation layers alternately with structured metal layers. Finally thesacrificial material structure is removed from the back side of thecomposite board. The cavity thereby produced can then be configured toform a microwave insulation region.

This method can have the advantage that a considerable cost saving canbe made by producing semiconductor modules in parallel on onesubcarrier. The method also can have the advantage that as a result of asimple layout, it can be ensured that the sacrificial material structureis not coated with thin film over a small area, for example, of lessthan 100 μm² and consequently is subsequently freely accessible forsuitable chemicals for dissolving the sacrificial material structure. Itis furthermore possible that the back side of the semiconductor modulecan be processed completely independently of the upper side of thesemiconductor module. The sacrificial material structure is then removedby suitable solvents or etching agents. A defined resonance cavityhaving the desired ∈_(r)=1 for air is left behind.

It is not actually necessary to close the access opening but the cavitycan be filled with a suitable liquid having a predetermined ∈_(r) andthen closed. This liquid whose relative dielectric constant ∈_(r) isbetween 1≦∈_(r)≦3.5, produces a liquid-filled cavity. This liquid-filledcavity initially has an opening toward the back side of thesemiconductor module which, however, can be terminated by acorresponding dielectric lens structure in a completely liquid-tightmanner. The cavity thereby produced can thus be configured as amicrowave insulation space of a patch antenna structure, a strip antennastructure, and/or a slotted antenna structure with radiation plate.

The material properties of the sacrificial material are on the one handa temperature resistance as far as at least the curing temperature ofthe plastic package molding compound and the dielectric. Furthermore,the sacrificial material should be resistant and chemically inert to theplastic package molding compound, the dielectric, and the processchemicals of the thin-film technology, as well as the chemicals fordeveloping a photoresist, for corresponding electrolytes, and forstripping chemicals. Finally, the sacrificial material should bechemically soluble/etchable in solution/etching which does not attack,or attacks to a sufficiently small degree the thin-film layers such asthe dielectric and metal layers and the plastic package moldingcompound. The surrounding compound can be predetermined by the plasticpackage molding compound so that the cavity produced is configured toform a resonance cavity for extremely high frequencies in the plasticpackage molding compound of the plastic casing.

The cavity thereby produced can be covered by a radiation plate and anaperture or a slot for coupling in the microwave energy can be disposedopposite to the radiation plate. A polarized and aperture-coupled patchantenna structure can be implemented with a cavity thus configured. Ifthe cavity in a plastic package molding compound is closed by theradiation plate, the height of the cavity corresponds to the thicknessof the composite board, the composite board defining the couplingfrequency. The position of the radiation plate can be varied byconfiguring a lens which terminates the cavity in the plastic casing sothat the spacing between aperture and radiation plate can be matched todifferent coupling frequencies.

The sacrificial material structure can be formed from polyamide, whichadvantageously facilitates the removal of the sacrificial materialstructure from the plastic package molding compound using a solvent.Polyamide is sufficiently thermally stable and can be dissolved both inacetone and in butyrolactone whereas typically curable dielectrics suchas polyimide, BCB, PBO, and all other metals contained in themultilayered conductor track structure are resistant to acetone andbutyrolactone.

A first dielectric can also completely cover and thereby protect thesacrificial material. This now allows greater degrees of freedom in thechoice of sacrificial material since the condition that the sacrificialmaterial must be resistant to all thin-film process chemicals iseliminated. However, before the sacrificial material can be dissolvedwith suitable chemicals, before removing the sacrificial materialstructure, the plastic package molding compound or the protective layeris at least partly removed from the back side of the sacrificialmaterial structure, by, for example, laser ablation. An opening in thedielectric is thereby made through which the means for removing thesacrificial material can dissolve out or etch out the sacrificialmaterial structure. In the simplest case, the sacrificial materialstructure has a glucose-based or salt-based water-soluble sacrificialmaterial so that water can be used as solvent.

Before removing the subcarrier, the composite board or a laminate ofsemiconductor chips and plastic package molding compound is thinned tosuch an extent from the back side that the thickness is matched to thedifferent coupling frequencies of an antenna structure. By differentlyconfiguring the thickness of a plastic package molding compound of aplastic casing, it is possible to also provide different antennastructures for different frequencies.

A method for fabricating a semiconductor module with components formicrowave engineering in a plastic package molding compound where amicrowave insulation region is provided in one of the insulation layersinstead of a cavity structure, includes the following process steps.Firstly, as in the above method, components of a semiconductor moduleincluding at least one semiconductor chip for extremely high frequencieswith electrodes on an active upper side and/or including passivecomponents with electrodes on a connecting plane are fabricated. Thesemiconductor chips and the passive components with their electrodes arethen applied to an upper side of a subcarrier. The components are thenembedded or laminated in a plastic package molding compound. Thepreparation and embedding of a sacrificial material structure can beomitted in this method.

The subcarrier can then be removed so as to expose a principal surfaceincluding plastic package molding compound and electrodes of thesemiconductor chip and/or the passive components so as to form acomposite board. A multilayered conductor track structure is applied tothe principal surface or the upper side of the composite board byapplication of structured insulation layers and structured metal layersalternately to the upper side of the composite board. In this case, atleast one of the insulation layers is made of a dielectric material formicrowave components.

This means that this insulation layer has a microwave insulation regionwith a relative dielectric constant ∈_(r) between 1≦∈_(r)≦3.5continuously or at least in parts. Finally, an upper metal layer isstructured to form a radiation plate of a patch antenna structure.

Since an insulation layer having a suitable dielectric constant isprovided from the outset in this method, it is possible to form aslotted electrode in a deeper metal layer opposite to the radiationplate, which forms an aperture whose slot is intersected by a spacedstripline for a polarized aperture coupling of a polarized andaperture-coupled patch antenna in a metal layer located furtherthereunder. Consequently, at least three structured metal layers areprovided on the principal surface or the upper side of the compositebody, the lowermost metal layer having the stripline from one electrodeof a semiconductor chip to the patch antenna structure. A middle metallayer forms the aperture or the slotted electrode in the area of thepatch antenna. An uppermost metal layer with interposed insulation layerhaving a suitable relative dielectric constant exhibits the structure ofthe radiation plate. A radiation plate of this type can be constructedas square but also circular or polygonal.

The spacing between the aperture and radiation plate can be matched todifferent coupling frequencies of the antenna coupling region byarranging the aperture on different metal layers of the multilayeredconductor track structure on the principal surface. This spacing can beadjusted by the thickness of the insulation layer provided there.

In a further embodiment of the method, the radiation plate is arrangedon a base surface of a dielectric lens, wherein the spacing betweenaperture and radiation plate is matched to the coupling frequency of theantenna coupling region by different shaping of the base surface of thedielectric lens.

The same procedure as in the first process example is adopted for theproduction of the plastic casing, whereby semiconductor chips such as aVCO and/or DSP semiconductor chip for extremely high frequencies areembedded in a plastic package molding compound, these semiconductorchips being arranged adjacent to the microwave insulation region withantenna structure.

In addition, both in the first process example and in the presentprocess example, antenna arrays are provided in the microwave insulationregion and antenna structures are arranged in a square or in arectangle, at least one antenna structure being arranged in therespective corners of the square or the rectangle. It is also possibleto arrange an antenna array in the microwave insulation region in theplastic package molding compound of the semiconductor module, whereantenna structures are arranged in an edge zone of the semiconductormodule in a line. For both illustrative embodiments of the method forproducing a semiconductor module, surface-mountable solder balls can beprovided partly as external contacts and partly as mechanical supportsand/or spacers and soldered on to the semiconductor module. It is alsopossible, relatively independently of the two methods, to apply heatsinks whose cooling fins extend over the edge sides of the semiconductormodule and are fixed to a superordinate printed circuit board for betterstabilization of the component. This fixing can be effected by solderballs being applied to the fins, equally the fixing can be carried outby adhesion. Furthermore, the semiconductor module can be mounted on aninner side of a screening case, where a suitable thermally conductingplastic or solder is used for flush mounting or bonding to the innerside. The heat sink together with a patch antenna structure can then bedisposed on the back side of the semiconductor module.

Before components are applied, the upper side of the subcarrier islaminated with an adhesive film to prepare the subcarrier for receivingcomponents of the semiconductor module, which has the advantage thatlarge-area subcarriers can be prepared, which are then split intosubcarriers for a limited number of semiconductor modules. According toan illustrative embodiment of the method, during fabrication of themultilayered conductor track structure, passive thin-film elements aredisposed between the insulation layers before and/or during applicationof the metal layers. These thin-film elements can be used for matchingthe semiconductor module to superordinate circuits and/or replacediscrete, passive components provided in these semiconductor modules.

The embedding of the components in a plastic package molding compoundcan be carried out using a compression molding method and/or adispensing method and/or a laminating method. In order to laminate thecomponents into a plastic package molding compound, a correspondingplastic laminate is heated and laminated onto the subcarrier loaded withcomponents.

FIG. 1 shows a schematic cross section through a semiconductor module 1of a first illustrative embodiment. The semiconductor module 1 isconstructed on the basis of a plastic casing 7 and in this illustrativeembodiment, has a large-area metal heat sink 43 on its back side 42,which at the same time can form a groundplane for an antenna structure34 to increase the directionality of the antenna structure 34.

The plastic casing 7 can have the advantage that the components 6 formicrowave engineering can be arranged close to one another and inparticular, a connecting lead 65 between an electrode of a VCOsemiconductor chip 12 shown here and the antenna structure 34 can beexecuted as extremely short or as a planar optimized waveguide so thatparasitic effects and reflections may be minimized. A signal amplifierand/or a frequency multiplier with external clock signal supply can alsobe provided as the semiconductor chip 12.

A further advantage that may be realized with the first illustrativeembodiment is that an almost flat conductor track structure 13 inthin-film technology not described in detail here can be arranged on aprincipal surface 8 of the plastic casing 7, which is adapted to theneeds of a microwave antenna structure 34. Thus, transmission lines 67can be implemented directly on the principal surface 8 or on a thininsulation layer applied thereon, especially as these principal surfaces8 are formed from an upper side 9 of a plastic package molding compound10 and from upper sides 11 of the semiconductor chips 12 and 22 embeddedin the plastic package molding compound 10. Disposed on this first lowermetal layer 14 with the corresponding transmission lines 67 betweenelectrodes 48 of the semiconductor chips 12 and 22 among one another andwith the antenna structure 34 is an insulation layer 17 whichelectrically insulates a second metal layer 15 from the first metallayer 14.

A radiation plate 21 of a patch antenna 20 is structured on an uppermetal layer. This upper metal layer with the radiation plate 21 has aspacing from the middle metal layer 15. The interposed insulation layerincludes an insulation material suitable for microwave engineering wherethe relative dielectric constant ∈_(r) for this insulation layer 16 isbetween 1≦∈_(r)≦3.5. The thickness d of this insulation layercorresponds to the spacing a between the radiation plate 21 and aslotted electrode 28 with a coupling slot 27 in the metal layer 15. Thiscoupling slot 27 forms an aperture 26 through which the microwave energyfrom the connecting lead 65 is coupled into the intermediate spacebetween the radiation plate 21 and the slotted electrode 28. In thisfirst illustrative embodiment, a dielectric lens 33 is arranged abovethe radiation plate 21, whose base surface 35 is arranged parallel tothe radiation plate 21 and whose contour 66 is used to improve thedirectionality of the antenna structure 34. In a variant not shown theradiation plate 21 is integrated into the dielectric lens 33 by analogywith the following descriptions of FIGS. 8 and 10.

These semiconductor modules 1 can be fabricated at the same time on thebasis of a composite board 49, also called a panel, including plasticpackage molding compound 10 and semiconductor chips 12 and 22. For thispurpose, for semiconductor modules 1, a multilayered conductor trackstructure 13 with transmission leads 67 in a first metal layer 14 on astructured insulating layer optionally applied to the surface 8, isapplied to the principal surface 8 formed by the upper side 50 of thecomposite board 49. Furthermore, a second metal layer 15 is provided forapplying a slotted electrode 28. The radiation plate 21 is disposed in athird metal layer and insulation layers 16 and 17 are applied betweenthe metal layers. Furthermore, it is possible to use the second and/orthird metal layer outside the antenna region for connecting leads of theindividual components or matching structures. The cooling plate 43 shownin FIG. 1 can be attached to the back side 51 of the composite board 49,which forms the back side 42 of the plastic casing, for thesemiconductor modules 1. The dielectric lens 33 can also be bonded withits base surface 35 to the radiation plate 21 before the composite board49 is separated into individual semiconductor modules 1.

FIG. 2 shows a schematic cross section through the semiconductor module1 according to FIG. 1 with possibilities for attaching connectingelements. Components having the same functions as in FIG. 1 arecharacterized by the same reference numerals and are not additionallyexplained. As shown in this illustrative embodiment on the left-handside in FIG. 2, the insulation layer 16 can be partially or selectivelyremoved down to the structured metal layer 15 to create a contactconnecting surface 68 for a connecting element, where a connection tothe lower metal layer 14 can be created by a contact via 69. It isfurther possible to design not only the metal layer 15 but additionalmetal layers for external contacts, but these are not shown separatelyhere for reasons of clarity.

A further variant for external contacts is shown on the right-hand sidein FIG. 2, independent of the left-hand side. The multilayered conductortrack structure 13 projects over the principal surface 8 so that acontact connecting surface 68, for example, for a solder ball contact isprovided which is then connected to the structured metal layer 14 asshown here. Further metal layers can be used for contact connectingsurfaces in exactly the same way, which is not shown here. The overhangof the conductor track structure can easily be produced using asacrificial layer similar to the coupling cavity, as describedpreviously.

FIG. 3 shows a schematic cross section through the semiconductor module1, according to FIG. 1, with a connecting element 65 connecting to asurface-mountable external contact 40, which together with a bond wire70 is embedded in an additional second plastic package molding compound19. All other components which have the same function as in FIGS. 1 and2 are characterized by the same reference numerals and are notadditionally explained.

FIG. 4 shows a schematic cross section through the semiconductor moduleaccording to FIG. 1 which, by analogy with a COB assembly (chip onboard) on a superordinate printed circuit board 76, is connected to bondwire connecting elements 70 which are protected with a globtop cover 92,as shown here. For this purpose, the printed circuit board 76 has aconnecting contact surface 77 on its upper side 84, which, as shownhere, is electrically connected to a flat external contact 40 on theunderside 87 of the printed circuit board 76 by a contact via 85 throughthe printed circuit board 76. Here, as in FIG. 3, the middle metal layer15 is used to electrically couple the semiconductor module 1 to aconnecting contact surface 77 of a superordinate printed circuit board76.

In addition, in this illustrative embodiment, the semiconductor module 1has a further metal layer 86 on its back side, which can be structuredor can cover the entire back side 42 of the plastic casing of thesemiconductor module 1. In this illustrative embodiment in accordancewith FIG. 4, this is at least thermally connected to a large-areacontact layer 89 on the upper side 84 of the superordinate printedcircuit board 76 by a thermally conducting adhesive layer 88 or solderlayer so that heat can be delivered by contact vias 90 to a coolingsurface 91 disposed on the underside 87 of the printed circuit board 76,which for its part is in operative connection with a heat sink notshown. However, the contact vias 90 can also be used as electricalcontact vias provided that a conducting adhesive is used as adhesivelayer 88. In addition, the metal layer 86 can be configured so thatinstead of the large-area contact layer 89, individual connectingcontact surfaces on the upper side 84 of the printed circuit board 76can be connected to correspondingly structured contacts on the back side42 of the plastic casing 7. In addition, the illustrative embodimentshown here in accordance with FIG. 4 has one or more contact vias 82which connect the metal layer 86 on the back side 42 of the plasticcasing 7, for example, to the middle metal layer 15 within themultilayered conductor track structure 13. Consequently, thesemiconductor module 1 opens up multiple possibilities for optimallyconfiguring a microwave semiconductor module.

FIG. 5 shows a schematic cross section through the semiconductor module1 in accordance with FIG. 1 with a solder ball connecting element 39from a contact connection surface 68 of the lower metal layer 14 on theprincipal surface 8 of the plastic casing 7 to a connecting contactsurface 77 on the upper side 84 of a superordinate printed circuit board76. Components having the same functions as in the preceding figures arecharacterized with the same reference numerals and are not explainedadditionally.

FIG. 6 shows a schematic cross section through a semiconductor module 2of a second illustrative embodiment. This semiconductor module 2 is alsobased on a plastic casing 7 with a composite board 49 having a back side51 and an upper side 50, a multilayered conductor track structure 13being disposed on the upper side 50. For this purpose, the upper side 50of the composite board 49 forms a principal surface 8 which is composedof the upper side 9, a plastic package molding compound 10, and activeupper sides 11 of semiconductor chips 12.

Unlike the first illustrative embodiment according to FIG. 1, theantenna coupling region 24 is not disposed in an insulation materialhaving a suitable relative dielectric constant but is formed by acoupling cavity 25 which is incorporated in the plastic package moldingcompound and has a relative dielectric constant of 1. Consequently, thecoupling frequency for the antenna structure 34 is principallydetermined by the thickness D of the plastic package molding compound 10for the composite board 49 of the plastic casing 7.

The coupling cavity 25 can be incorporated in the plastic packagemolding compound 10 from the back side 51 of the composite board 49 bylaser ablation or, if the configuration of the coupling cavity 25 ismore complex, it can be performed before completion of the compositeboard 49 by forming a sacrificial material structure in the plasticpackage molding compound 10. Suitable materials for this type ofsacrificial material structure are described above. The removal of thesacrificial material structure has also already been discussed indetail. The possibility of filling the forming cavity 25 with a liquidfor adjusting a suitable relative dielectric constant has also beendiscussed so that this will not be discussed again to avoid repetition.

Located in the area of the multilayered conductor track structure is aslotted antenna structure 23 by which the energy is coupled in from thesemiconductor chip 12 to the antenna structure 34 via the cavity 25.Whereas the height h of the cavity is determined by the thickness D ofthe composite board 49, in this illustrative embodiment the spacingbetween a slotted electrode 28 with the aperture 26 and a radiationplate 21 is larger since an insulation layer 16 with a suitable relativedielectric constant ∈_(r) is disposed between the cavity 25 and theaperture 26. The radiation plate 21 terminates the coupling cavity onthe back side 51 of the composite board 49. The directionality of theantenna is intensified by a dielectric lens 33 which is fixed on theradiation plate 21 with the aid of an adhesive 72. In this illustrativeembodiment, the remaining back side surface of the plastic casing 7 iscovered by a structured metal layer 54 on which a heat sink 43 isarranged by a heat-conducting layer 73 of filled adhesive and/or soldermaterial.

At the same time, the upper side 71 of the multilayered conductor trackstructure 13 forms the back side 47 of the semiconductor module 2 and isloaded with external contacts 40, which are solder balls 39 for example,of which some solder balls serve as mechanical supports 41, especiallyin the vicinity of the antenna structure 34 and other solder balls 39are electrically connected as external contacts 40 to a metal layer 14and/or 15. Through this arrangement of the external contacts 40 and themechanical supports 41 in the form of solder balls, it is possible tofix the entire semiconductor module 2 on an upper side of asuperordinate printed circuit board using a single soldering process.

FIG. 7 shows a schematic cross section through the semiconductor module2 according to FIG. 6 with a first modification of the antenna structure34. This modification involves arranging the slotted electrode 28 withaperture 26 directly on the upper side 50 of the composite board 49 oron the principal surface including plastic package molding compound 10and semiconductor chip 12. Consequently, the spacing a between theradiation plate 21 covering the cavity 25 and the slotted electrode 28corresponds to the thickness D of the plastic package molding compound10 and at the same time also forms the height h of the coupling cavity25. With otherwise the same structure of the plastic casing 7, as shownin FIG. 6, the output power may be optimized with this modification ofthe antenna structure 34 with antenna coupling region 24.

FIG. 8 shows a schematic cross section through a semiconductor module 2according to FIG. 6 with a second modification of the antenna structure34. Components having the same functions as in the preceding figures arecharacterized with the same reference numerals and are not explainedadditionally. In this illustrative embodiment, the radiation plate 21 isintegrated in the base region of the dielectric lens 33 so that the basesurface 35 and the radiation plate 21 form a principal surface. The basesurface 35 of the dielectric lens is connected to the back side 51 ofthe composite body 49 by an adhesive layer 72 and terminates a couplingcavity 25 disposed in the plastic package molding compound 10.

FIG. 9 shows a schematic cross section through the semiconductor module2 according to FIG. 6 with a third modification of the antenna structure34. In this case also, components having the same functions as in thepreceding figures are characterized with the same reference numerals andare not explained additionally. In this illustrative embodiment, thedielectric lens 33 has a pedestal 80 in the base region on which theradiation plate 21 is fixed and which projects into the cavity 25 sothat even higher frequencies can be coupled via the antenna couplingregion 24 and the height h of the coupling cavity 25 can be configuredindependently of the thickness D of the composite board 49.

FIG. 10 shows a schematic cross section through the semiconductor module2 according to FIG. 6 with a fourth modification of the antennastructure 34. In this case, the dielectric lens 33 has an indentation 81in the area of the base surface 35 of the lens 33 which bears theradiation plate 21. Consequently, the spacing a between the slottedelectrode 28 and the radiation plate 21 is further enlarged so thatlower frequencies can be transmitted with this coupling cavity 25without the composite board needing to be unnecessarily thick.

FIG. 11 shows a schematic cross section through a semiconductor module 3of a third illustrative embodiment. Components having the same functionsas in the preceding figures are characterized with the same referencenumerals and are not explained additionally.

This third illustrative embodiment differs from the second illustrativeembodiment in that cooling fins 44 are disposed on the heat sink 43 andthat the microwave insulation region 18 is formed below the radiationplate 21 by plastic package molding compound 10. However, at least inthe area of the antenna structure 34, this plastic package moldingcompound 10 has a relative dielectric constant ∈_(r) between1≦∈_(r)≦3.5, without forming a cavity. Plastic foams can be used forthis purpose, which replace the plastic package molding compound 10 inthis antenna structure 34, at least in the antenna coupling region andhave a suitable relative dielectric constant ∈_(r).

FIG. 11 also shows a contact via 82 from the metal layer 14 on the upperside 50 of the composite board to the metal layer 54 on its edge side51. EMC shielding can be achieved hereby. Furthermore, similar externalcontacts as shown in FIGS. 2, 3, 4, and/or 5 can be formed by thesecontact vias and structuring of the metal layer 54 outside the antennacoupling region.

FIG. 12 shows a schematic view of the semiconductor module 3 from below,according to one of the illustrative embodiments. In this case, theoutlines of the high-frequency components 6, such as the semiconductorchips 12 and 22, for example and the antenna structures 34 arecharacterized by dashed lines, especially as these are partiallyembedded in the plastic package molding compound 10 and/or like theradiation plates 21 on the upper side of the semiconductor module 3 notshown here, which are arranged opposite to the back side 47 of thesemiconductor modules 1 to 6 shown here.

In this view of the illustrative embodiments from below, four patchantennas 20 with their radiation plates 21 are arranged in a line 38 inan edge zone 37 of the semiconductor module 3 in an antenna array. Theedge zone 37 has solder balls 39 which serve as mechanical supports 41whereas the region in which the semiconductor chips 12 and 22 areembedded also has solder balls 39 which form electrical externalcontacts 40 of the semiconductor module 3. The ordered arrangement ofthese patch antennas 20, e.g. in a line 38, as shown here, intensifiesthe directionality of the antennas, whereby such an arrangement of patchantennas is used for distance radar equipment and for directionalrecognition in vehicles. Such an “ordered arrangement” can also beappropriate on curves to achieve improved directional and/or positionalresolution by dynamic viewing of the signal profiles of the individualpatch antenna signals.

The signal leads 83 from and/or to the semiconductor amplifiers such asVCO, from and/or to the individual patch antennas can easily be designedaccording to the criteria of coplanar waveguides or striplines. Matchedsignal splitting and/or signal combining can be achieved by theoptionally applied thin-film technology of the conductor track structure13. As a result of the short and exact lead structures 13, phase anglesof the transmitted signal and/or received signal or phase angles of theindividual patch antenna signals can be detected particularlyaccurately. All time-critical signals in the GHz range can be evaluatedand processed immediately in a DSP (22) and passed on in largelydelay-uncritical signals, which can be in digital form, via leadstructures 13 and external contacts 40 to a superordinate printedcircuit board for further processing.

FIG. 13 shows a schematic cross section through a semiconductor module 4of a fourth illustrative embodiment of the invention. The semiconductormodule 4 includes a semiconductor chip 93 which is a current switchingdevice and can be used in power management applications for example. Themodule 4 is not designed for microwave engineering applications and doesnot include an antenna.

This semiconductor module 4 is also constructed on the basis of aplastic casing 7, where the back side 51 of the composite board 49 isconnected via a metal layer 54 and a thermally conducting layer 73 tothe inner side 46 of a screening case 45 which projects over the edgesides 52 and 53 of the plastic casing and forms side walls 74 and 75,which partially enclose an interior space which can receive thesemiconductor module.

The sides 74 and 75 on a superordinate circuit board 76 of a customerare at the same time soldered to the external contacts 40 of thesemiconductor module 4 on corresponding contact connecting surfaces 77.

A customer-specific heat sink 43 or a corresponding heat-conductingcustomer casing 79 can be fixed on the screening case 45 by aheat-conducting coupling layer 78. The specific thermal loads arereduced and the heat-transmitting surfaces are enlarged by the firstthermal spreading in the thermally good-conducting metal layer 54 and/orby the second thermal spreading in the screening case 45 so thatrelatively low demands with regard to heat conduction are imposed on theconnections 73 and even lower demands on the connection 78.

FIG. 14 shows a schematic cross section through a semiconductor module 5of a fifth illustrative embodiment also including a semiconductor chip93 as a current switch. Components having the same functions as in thepreceding figures are characterized with the same reference numerals andare not explained additionally.

In this illustrative embodiment, the plastic casing 7 is fixed on a heatsink 43 with the back side 51 of the composite board 49 whereby coolingfins 44 are arranged adjacent to the edge sides 52 and 53 of the plasticcasing 7 and bear solder balls 39 as mechanical supports 41. Thesesolder balls 39 are used to fix the cooling fins 44 on connectingcontact surfaces 77 on a customer-specific superordinate printed circuitboard 76. In an illustrative embodiment not shown, the mechanicalsupports 41 can be implemented by adhesion or crimping. Thisadditionally allows mounting of the heat sink after soldering of thesemiconductor module onto the superordinate printed circuit board 76.

The semiconductor module 5 based on a plastic casing 7 is disposedbetween the cooling fins 44. In this illustrative embodiment, inaddition to the heat sink 43, it is also possible for a heat-conductingcustomer casing 79 to be arranged on the heat sink 43 by aheat-conducting coupling layer 78.

FIG. 15 illustrates a schematic cross section through a semiconductormodule 100 of a sixth illustrative embodiment. Components having thesame functions as in the preceding figures are characterized with thesame reference numerals and are not explained additionally.

The semiconductor module 100 includes a semiconductor chip 12 andelectromagnetic screening which is provided by the second metal layer 54disposed on the second principal surface 42 of the plastic casing 7 ofthe semiconductor module 100, through contact 82, metal layers 14 and 15positioned on the first principal surface 8 of plastic casing 7 andexternal contact 103. The external contact 103 may be connected to theground plane of a superordinate or higher-level circuit board on whichthe semiconductor module 100 is mounted.

In the sixth illustrative embodiment, the first principal surface 8includes an upper side 9 of a plastic package molding compound 10 andthe active side 11 of the semiconductor chip 12. The active side 11 ofthe semiconductor chip 12 and the upper side 9 of the plastic packagemolding compound 10 are generally coplanar. The second principal side 42includes a back side 51 of the plastic package molding compound 10 andthe back side 101 of the semiconductor chip 12. This arrangement of anexposed back side 101 of the semiconductor chip 12 reduces the thermalpath between the semiconductor chip 12 and the heat sink 43 positionedon the second principal surface 42 of the semiconductor module 100.

In further illustrative embodiments not shown in the figures, the backside 101 of the semiconductor chip 12 is embedded within the plasticpackage molding compound 10. In these illustrative embodiments, thesecond principal surface 42 of the plastic casing 7 includes onlyplastic package molding compound 10. The plastic package moldingcompound may electrically isolate the back side 101 of the semiconductorchip from the second metal layer 54.

The second metal layer 54 disposed on the second principal surface 42extends over the whole of the second principal surface 42 of thesemiconductor module 100.

The semiconductor module 100 also includes at least one through contact82 which extends from the second principal surface 42 to the firstprincipal surface 8 and which is embedded within the plastic packagemolding compound 10. The through contact 82 is in electrical contactwith the second metal layer 54 and with the structured first metallayers 14, 15 positioned on the opposing first principal surface 8 aswell as external contact 103. The second metal layer 54 may be connectedto ground via the through contact 82 and the multilevel conductor trackstructure 13 positioned on the first principal surface 8. Thisarrangement provides the semiconductor module 100 with electromagneticscreening.

Through contacts 82 may be provided which are arranged at intervalsaround the side faces of the semiconductor chip. Each through contact 82may be connected to ground so that the through contacts 82 and thesecond metal layer 54 provide a Faraday cage type arrangement.

The semiconductor module 100 also includes a heat sink 43 with coolingfins 44 which is attached to the second metal layer 54 by a layer ofelectrically non-conductive adhesive 72. The heat sink 43 iselectrically isolated from the second metal layer 54 and theelectromagnetic shielding structure 102 in the sixth illustrativeembodiment.

The semiconductor 100 may be used to accommodate a semiconductor chip 12which should be protected from external electromagnetic radiation.Alternatively, the semiconductor chip 12 may itself emit electromagneticradiation whose emission range should be limited by the use of a moduleincluding an electromagnetic shielding structure.

While the invention has been described in detail and with reference tospecific illustrative embodiments thereof, it will be apparent to oneskilled in the art that various changes and modifications can be madetherein without departing from the spirit and scope thereof.Accordingly, it is intended that the present invention covers themodifications and variations of this invention provided they come withinthe scope of the appended claims and their equivalents.

What we claim is:
 1. A semiconductor module including components in aplastic casing, wherein said semiconductor module comprises: a plasticpackage molding compound; a semiconductor chip embedded in the plasticpackage molding compound; a first principal surface including an upperside of the plastic package molding compound and at least one activeupper side of the semiconductor chip; a second principal surfaceincluding a back side of the plastic package molding compound; amultilayered conductor track structure disposed directly on the firstprincipal surface, including structured insulation layers and structuredfirst metal layers arranged in an alternating fashion; and a secondmetal layer disposed on the second principal surface.
 2. Thesemiconductor module according to claim 1, wherein the semiconductorchip includes a voltage controlled oscillator (VCO).
 3. Thesemiconductor module according to claim 1, wherein the semiconductorchip includes a digital signal processor semiconductor chip (DSP). 4.The semiconductor module according to claim 1, wherein the semiconductorchip includes a digital signal processor semiconductor chip (DSP) andfurther includes active and/or passive components embedded in theplastic package molding compound.
 5. The semiconductor module accordingto claim 1, further including surface-mountable solder balls which areprovided as external contacts on a circuit board and as mechanicalsupports and/or spacers of the semiconductor module.
 6. Thesemiconductor module according to claim 1, further including at leastone through contact extending from the second metal layer on the secondprincipal surface to the structured metal layers disposed on said firstprincipal surface.
 7. The semiconductor module according to claim 1,wherein the second principal surface includes a rear side of thesemiconductor chip and the plastic package molding compound.
 8. Thesemiconductor module according to claim 1, wherein the multilayeredconductor track structure is positioned on both the active upper side ofthe semiconductor chip and the plastic molding compound of the firstprincipal surface, and the second metal layer is disposed on the backside of the semiconductor chip and the plastic package molding compoundof the second principal surface.
 9. A semiconductor module havingcomponents in a plastic casing, the semiconductor module comprising: aplastic package molding compound; a semiconductor chip; a firstprincipal surface including an upper side of the plastic package moldingcompound and at least one active upper side of the semiconductor chip; asecond principal surface including a back side of the plastic packagemolding compound; a multilayered conductor track structure disposeddirectly on the first principal surface; and a heat sink disposed on thesecond principal surface.
 10. The semiconductor module according toclaim 9, wherein the heat sink includes cooling fins between which theplastic package molding compound is disposed.
 11. The semiconductormodule according to claim 9, wherein the heat sink is a screening caseand the plastic package molding compound is disposed on an inner side ofthe screening case.
 12. The semiconductor module according to claim 9further including a second metal layer disposed directly on the secondprincipal surface.
 13. The semiconductor module according to claim 12,wherein the second metal layer is electrically isolated from the heatsink.
 14. The semiconductor module according to claim 12, wherein thesecond metal layer is electrically conductively connected to themultilayer conductor track by a through contact extending from thesecond principal surface to the first principal surface.
 15. Thesemiconductor module according to claim 10 further including externalcontacts, wherein the cooling fins of the heat sink include solder ballsand form a plane with the external contacts in which the externalcontacts and the solder balls of the heat sink are surface-mountable.16. The semiconductor module according to claim 9, wherein the secondprincipal surface includes a rear side of the semiconductor chip and theplastic package molding compound.
 17. The semiconductor module accordingto claim 12, wherein the multilayered conductor track structure ispositioned on both the active upper side of the semiconductor chip andthe plastic molding compound of the first principal surface, and thesecond metal layer is disposed on the back side of the semiconductorchip and the plastic package molding compound of the second principalsurface.